A color picture tube includes an electron gun for generating and directing three electron beams to a screen of the tube. The screen is located on the inner surface of a faceplate of the tube and is made up of an array of elements of three different color emitting phosphors. An apertured mask, which may be either a shadow mask or a focus mask, is interposed between the gun and the screen to permit each electron beam to strike only the phosphor elements associated with that beam. A shadow mask is a thin sheet of metal, such as steel, that is contoured to somewhat parallel the inner surface of the tube faceplate. A focus mask comprises dual sets of conductive lines that are perpendicular to each other and usually separated by an insulative layer.
One type of color picture tube has a cylindrical faceplate and a tensioned shadow mask mounted therein. In order to maintain the tension on the mask, the mask must be attached to a relatively massive support frame. Although such tubes have found wide consumer acceptance, there is still a need for further improvement in tube types having cylindrical faceplates, to reduce the weight and cost of the mask-frame assemblies in such tubes.